Sewing machine



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SEWING MACHINE Filed July 21, 1932 6 Sheets-$heet 6 C W Mug/A92" Patented Apt". 10, 1934 UNITED STATES SEWING MACHINE Charles W. Mueller, St. Louis, Mo., assignor to Lewis Invisible Stitch Machine Company, St. Louis, Mo., a. corporation of Maine Application July 21, 1932, Serial No. 623,364 12 Claims. (01.112-177) This invention relates to new and useful improvements in blind stitch sewing machines generally, although more particularly to machines for blind stitching comparatively narrow hems along the bottoms of skirts and other articles of wearing apparel.

Among the several objects of the invention are to provide a reciprocatory device for forming a ridge in the hem and body fabric and for alternately raising the ridge to diiferent planes whereby the needle during certain strokes will engage both the body fabric and the hem and during alternate strokes will engage the hem only; to provide a vertically reciprocatory plunger for forming the ridge; and to provide a novel and simple means for alternately raising and lowering bodily the plunger during its reciprocatory strokes. Y

With these and other objects in view which will more fully appear, the nature of the invention will be more clearly understood by following the description, the appended claims, and the several views illustrated in the accompanying drawings. 1

In the accompanying drawings:-

Figure 1 is a front elevation of a sewing machine constructed in accordance with my invention,

Figure 2 is a left hand elevation thereof, the go work plate and hemmer being removed,

Figure 3 is a partial longitudinal sectional view taken through the machine, I

Figure 4 is a horizontal sectional view taken above the work plate,

Figure 5 is a vertical sectional view taken through the base and standard and showing particularly the plunger adjusting means,

Figure 6 is a detail top plan view of the means for adjusting andsetting the plunger adjusting means,

Figure 7 is an enlarged sectional view showing the plunger at the upper end of one stroke and showing the needle passing through the body fabric and the hem,

Figure 8 is a similar view but showing the plunger at the upper end of another stroke, and showing the needle passing through the hem only,

Figure 9 is an enlarged plan view of a hemmed by a line of single thread blind stitches in which alternate needle thread loops enter and emerge from'the upper face of the body fabric and then pass through the hem fold, the remaining needle thread loops passing through the hem fold only. A seam of this type forms the subject matter of my'Patent 1,903,933, April 18, 1933. The body fabric A is formed along one edge with a hem B which includes a hem fold 5 and an inturned edge portion 6. The single thread 7 which forms the connected stitches is formed into a series of equally spaced alternate needle thread loops 8 and 9. Each needle thread loop 9 is projected through the previously formed needle thread loop 8 and thence upwardly through the portions 5, 6 ofthe hem, the needle thread loop 9 thence being laid against the outer face of the hem 5 and the bight 9 being positioned under the inner edge portion so as to be concealed from view. The next adjacent needle thread loop 8 enters and emerges from the upper face of the body fabric at a point under the hem and is then projected upwardly through the hem portions 5, 6, the needle thread loop 8 then being positioned against the outer face of the hem fold 5 and the bight 8 thereof being disposed under the inner edge portion of the hem so as to be concealed from view, the connecting portions 10' between adjacent needle thread loops 8, 9 'extending lengthwise of the seam and being also disposed under the inner edge portion of the hem so as to be also concealed from view. It will be observed that the needle thread loops are disposed in planes diagonal to the line of feed.

The machine for forming the above described seamed hem, and which forms the subject matter of this application, comprises aframe C including a base 11 from the right hand end of which rises a hollow standard or post 12, an overhanging arm 13 which is secured at one end to the standard, and a stitching head 14 which is secured to the free end of the overhanging arm.

The base 11 includes a top 15, front and rear depending walls 16, 17 and end walls 18, 19.

Rigidly att'ached to the lower end of the stitching head 14 is a presser foot D having its front right hand corner cut away to form a resultant front transverse wall or edge 20. A slot 21 is formed in the foot, and this slot extends rearwardly from the front wall or edge 20. Directly in rear of the slot 21, the foot is formed with a top feed slot 22, and at one side of the slot 21 the foot is formed with a looper clearance slot 23.

A main shaft 24 extends longitudinally within the overhanging arm 13, the right hand end ex tending through the upper end of the hollow standard 12 and the left hand end extending into the stitching head14. a. v

A single thread stitch forming mechanism E is mounted on the stitching head and includes an oscillatory curved needle 25 and a cooperating fi-motion looper 26. The needle is fixed to a needle lever 27 which is pivoted on the stitching head 14 above the presser foot D, and the lever is operated from the main shaft 24 through the medium of well known driving connections indicated generally by the numeral 28, the needle having its path of movement across the slot 21- of the foot.v The looper 26 is also operated from the main shaft through the medium of well known driving connections indicated generally by the numeral 29. It is sufilcient to state that the needlepartakes of a complete oscillation for each revolution of the main shaft.

Cooperating with the underface of the presser foot D to present the work to the needle is a vertically r-eoiprocatory work clamp F and a lower -motion feed dog G, and cooperating with the work clamp F to assist the lower feed dog G in feeding the work away from the needle is a 4imotion top feed dog H. A vertically reciprocable plunger I which operates in the slot 21 of the presser foot is timed to al ernately project first the hem B only and then the body fabric A together with the hem B into a ridge for penetration by the needle 25.

A work plate J is adjustably mounted on the base '11 of the machine frame below the presser foot D, and adjustably mounted on the work plate in front of the presser foot is a folder or hemmer K which in this instance is constructed to include a scroll and a core to form the infurned hem B. The nose of the folder is located directly in front of the slot 21 of the presser foot and is therefore immediately in front of the plunger I. The means of mounting the work plate J on the machine base 11 and the means of mounting the folder K on the work plate and in relation to the presser foot, embodies the subject matter of my co-pending application Serial No. 594,930; filed Feb. 24, 1932.

The mechanisms for operating the work clamp F, the lower feed dog G, and theplunger I are of known constructions and therefore a detail description thereof will be unnecessary.

The work clamp F is normally pressedupwardv 1y against thepresser foot D by a flat spring 30 as shown in Figure 3. r

The lower feed dog G is reciprocated vertically through the medium of a link 31 which is -pivoted at its upper end to the dog and at its lower end to one end of a bell crank lever 32 pivoted at its angle as at 33 to the shank or post 34 of the work clamp.) The other arm of the bell crank lever 32 is connected by a link 35'to a rock arm 36 fixed to a feed lift shaft 37 journaled in the base 11 of the machine frame and oscillated from the main shaft 24 by connections indicated generally at 38. The backward and forward movements of the feed dog G are created by a link 39iwhich is pivoted at one end to the dog and at the other end to a rock arm so fixed to a feed travel shaft 41 iournaled in the machine base 11 and oscillated from the main shaft 24; by connections indicated generally at 42. The feed dog G includes a fixed feed section as and a yieldable feed section 44, the former operating on the body fabric A at the left of the hem B and the latter operating on the hem B in rear of the path of reciprocation of the needle.

The work clamp F and the feed dog G are timed in the usual manner to respectively clamp the work against the presser foot D and thereby resist the penetrating stroke of the needle 25, and. to intermittently feed the hemmed goods from the folder K up to and beyond the needle of the a lift lever 46 which is pivoted at one end as at 4'7 to the end 18 of the base 11. The other end of the lever is formed with a cam groove dB in which is located a cam roller 49 journaled on a rock arm 50 fixed to one end of a shaft 51 journaled in rock arms of a cradle 52 pivoted in the base 11. The

cradle is rocked from the main shaft 2 to there-.

by bodily vary the vertical position of reciprocation of the plunger by a mechanism shown in my prior Patent 1,588,132, June 8, 1926. This mechanism includes a vertical cam roller shaft 53 which is constantly driven from the main shaft through the medium of a gear coupling 54 which reduces the speed of the cam roller shaft relative to the main shaft 24 by the ratio of l to 4. A hand adjustment indicated generally at 55 is associated with the upper end of the cam roller shaft 53 to vary the effective high point of reciprocation of the plunger and thereby vary the depth of needle penetration in the work. The plunger is reciprocated through the oscillations of the shaft 51, and this shaft is oscillated from the main shaft 24 by the connections indicated generally at 56. g The emotion top fee'd dog H is attached to the lower end of a vertical feed bar 57 having a sliding connection with a horizontal pivot 58 carried by the stitching head 14, the upper end of the bar being raised and lowered and moved backwardly and forwardly by a connection with the main shaft 24. This top feed dog H engages the hem B through the slot 22 in the presser foot D, and is timed to operate in unison with the lower feed dog G. From the foregoing it will be observed that the plunger is reciprocated during each revolution of the main shaft and that the vertical position of reciprocation of the plunger is alternately.

raised and 'lowered, thereby first projecting a ridge of the hem only into needle penetrating position, and then projecting a ridge which includes both the body fabric and thehem into needle penetrating position; that as the hem fold leaves the nose of the folder it is engaged by the lower feed and is fed rearwardly past the needle; that one section of the lower feed dog engages the hem directly in rear of the needle and by reason of the feed section being yieldable it will accommodate hems of different thicknessesand permit the main feed dog section to engage the body fabric, and that the top feed dog engages the hem in rear of the needle and cooperates with the lower feed dog to feed the work through the machine.

It is of course to be understood that the details of structure and arrangements of parts may be variously changed and modified without departing from the spirit and scope of my invention.

I claim:

1. In a blind stitch sewing machine, the combination with aistitch forming mechanism including an oscillatory needle; of a hemmer disposed in front of the needle; means for feeding the hemmed goods past the needle; a ridge forming device located below the needle and the goods for forming a ridge in the hem and body fabric; and means for reciprocating the ridge forming hem to different planes whereby the needle during certain strokes will engage the body fabric and the hem and during alternate strokes will engage the hem only.

2. In a blind stitch sewing machine, the combination with a stitch forming mechanism includ-' ing an oscillatory needle; of a hemmer disposed in front of the needle; means for feeding the hemmed goods past the needle including a lower feed dog and an upper feed dog, the upper feed dog engaging the hem in rear of the needle path;

I a ridge forming device located below the needle and the goods for forming a ridge in the hem and body fabric; and means for reciprocating the ridge forming device for alternately raising the body fabric and hem to different planes whereby the needle during certain strokes will engage both the body fabric and the hem and during alternate strokes will engage the hem only.

3. In a blind stitch sewing machine, the combination with a stitch forming mechanism including an oscillatory needle; of a hemmer disposed in front of the needle; means for feeding the hemmed goods past the needle; a vertically reciprocable plunger located below the needle and the goods for forming a ridge in the hem and body fabric; and means for reciprocating the plunger for alternately raising the body fabric and hem to different planes whereby the needle during certain strokes will engage both the body fabric and the hem and during alternate strokes will engage the hem only.

. 4. In a blind stitch sewing machine, the combination with a single thread chain stitch forming mechanism including an oscillatory needle and a cooperating looper; a hemmer disposed in front of the needle and including a tapering core and a surrounding scroll; means for feeding the hemmed goods past the needle; a ridge forming device located below the needle and the goods for forming a ridge in the hem and body fabric; and means for reciprocating the ridge forming device for alternately raising the body fabric and hem to different planes whereby the needle during certain strokes will engage both the body fabric and the hem and during alternate strokes will engage the hem only.

5. In a blind stitch sewing machine, the combination with a single thread chain stitch forming mechanism including an oscillatory needle and a cooperating looper; a hemmer disposed in front of the needle and including a tapering core and a surrounding scroll; means for feeding the hemmed goods past the needle including a lower feed dog and an upper feed dog, the upper feed dog engaging the hem in rear of the needle path; aridge forming device located below the needle and the goods for forming a ridge in the hem and body fabric; and means for reciprocating the ridge forming device for alternately raising the body fabric and hem to different planes whereby the needle during certain strokes will engage both the body fabric and the hem and' during alternate strokes will engage the hem only.

6. In a blind stitch sewing machine, the combination with a single thread chain stitch forming mechanism including an oscillatory needle and a cooperating looper; a hemmer disposed in front of the needle and including a tapering core and a surrounding scroll; means for feeding the hemmed goods past the needle including a lower feed dog andan upper feed dog, the upper feed dog engaging the hem in rear of the needle path; -a vertically reciprocable plunger located below the needle and the goods for forming a ridge in the hem and body fabric; and means for reciprocating the plunger for alternately raising the body fabric and hem to different planes whereby the needle during certain strokes will engage both the body fabric and the hem and during alternate strokes will engage the hem only.

7. In a blind stitch sewing machine, the combination with a stationary presser foot having a rearwardly extending slot in the front end thereof of a stitch forming mechanism disposed above the foot and including an oscillatory needle having its path of movement across the slotin the foot; a hemmer disposed in front of the needle and having its outlet nose located directly in front of the slot in the foot; means for feeding the hemmed goods past the needle; a ridge forming device operating in the slot of the foot directly in rear of the hemmer nose and directly below the needle; and means for reciprocating the ridge forming device for alternately raising the body fabric and hem to different planes whereby the needle during certain strokes will engage both the body fabric and the hem and during alternate strokes will. engage the hem only.

8.; In a blind stitch sewing machine, the combination with a stationary presser foot having a rearwardly extending slot in the front end thereof; of a stitch forming mechanism disposed above the foot and including an oscillatory needle having its path of movement across the slot in the foot; a hemmer disposed in front of the needle and having its outlet nose located directly in front of the slot in the foot; means. for feeding the hemmed goods past the needle; a vertically reciprocable plunger operating in the slot of the foot directly in rear of the hemmer nose and directly below the needle; and means for reciprocating the plunger for alternately raising the body fabric and hem to different planes whereby the needle during certain strokes will engage both the body fabric and the hem and during alternate strokes will engage the hem only.

9. In a blind stitch sewing machine, the combination with a stationary presser foot having a rearwardly ext-ending slot in the front end thereof; of a stitch forming mechanism disposed above the foot and including an oscillatory needle having its path of movement across the slot in the foot; a hemmer disposed in front of the needle and havingits outlet nose located directly in front of the slot in the foot; means for feeding the hemmed goods past the needle including a lower feed dog and an upper feed dog, the upper feed dog engaging the hem ,in rear of the needle path, a ridge forming-device operating in the slot of the foot directlyin rear of the hemmer nose and directly below the needle; and means for reciprocating the ridge forming device for alternately raising the body fabric and hem to different planes whereby the needle during certain strokes will engage both the body fabric and the hem and during alternate strokes will engage the hem only.

10. In a blind stitch sewing rmchine, the combination with a stationary presser foot having a rearwardly extending slot in the front end thereof; of a single thread chain stitch forming mecha nism' disposed above the foot and including an oscillatory needle and a co-operating looper; a hemmer disposed in front of the needle and having its outlet nose located directly in front of the slot in the foot, said hemmer including a tapering core and a surrounding scroll; means for feeding the hemmed goods past the needle;

LLO

a ridge forming device operating in the slot of the foot directly in rear of the hemmer nose and directly below the needle; and means for reciprocating the ridge forming device for alternately raising the body fabric and hem to different planes whereby the needle during certain strokes will engage both the body fabric and the hem and during alternate strokes will engage the hem only.

11. In ablind stitch sewing machine, the combination with a stationary presser foot having a rearwardly extending slot in the front end thereof; of a single thread chain stitch forming mechanism disposed above the foot and including an oscillatory needle and a co-operating looper; a hemmer disposed in front of the needle and having its outlet nose located directly in front of the slot in the foot, said hemmer including a tapering core and a surrounding scroll; means for feeding the hemmed goods past the needle including a lower feed dog and an upper feed dog, the upper feed dog engaging the hem in rear of the needle path; a ridge forming device operating in the slot of the foot directly in rear, of the hemmer nose and directly below the needle; and means for reciprocating the'ridge forming device hemmer disposed in front of the needle and having its outlet nose located directly in front of the slot in the foot, said hemmer including a tapering core and a surrounding scroll; means for feeding the hemmed goods past the needle; a vertically reciprocable plunger operating in the slot of the foot directly in rear of the hemmer nose and directly below the needle; and means for reciproeating the plunger for alternately raising the body fabric and hem to different planes whereby the .needle during certain strokes will engage both the body fabric and the hem and during alternate strokes will engage the hem only.

CHARLES W. MUELLER. 

